Ceratosoma sp. 2

Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Chromodorididae

PHOTO

Locality: Lembeh Strait, 15m, Indonesia, 12 November 2007. Length: 5 cm. Photographer: Ing. Harald Sapper.

This is an unnamed species of Ceratosoma which is apparently mimicking the sponge it feeds on. This is only a suggestion as we don't know what this species feeds on and we have little information on what most species of Ceratosoma feed on. However all species of Ceratosoma for which we have some information feed on sponges of the family Dysideidae, and if you have a look at a few examples on the Forum [see messages #2826, #11334, #19789] you will see this animals does indeed have a remarkable resemblance to such a sponge. I am sure the pale network in the skin is not a network of muscle fibres but a colour pattern to match the spongin fibres found in the fibrous skeleton of dysideid sponges.

Authorship details
Rudman, W.B., 2007 (April 26) Ceratosoma sp. 2 [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/cerasp2

Related messages


Re: A new sponge-mimicking Ceratosoma

April 30, 2007
From: Harald Sapper

Concerning message #19565:

Thank You! - I already thought they might be related but I had no idea they are this close. Next time I´ll try to take the photo on the sponge!
Kind regards
Harald

h.deepstop1@chello.at

Sapper, H., 2007 (Apr 30) Re: A new sponge-mimicking Ceratosoma. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19852

A new sponge-mimicking Ceratosoma

April 27, 2007
From: Ing. Harald Sapper


Hello!

Please can you help me to identify this sea slugs.

Locality: Lembeh strait, 15 m, Indonesia, 12 November 2006. Length: 5 cm. Photographer: Ing. Harald Sapper.

Thanks in advance
Harald Sapper

h.deepstop1@chello.at

Sapper, H., 2007 (Apr 27) A new sponge-mimicking Ceratosoma. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19565

Dear Harald,

These are both species of the chromodorid genus Ceratosoma. The orange-spotted animal is a colour form of Ceratosoma trilobatum, but the pale purple one is an unnamed species which is apparently mimicking the sponge it feeds on. I must warn you that this is a big guess on my part because we don't know what your animal feeds on and we have little information on what many species of Ceratosoma feed on. However all species of Ceratosoma for which we have some information feed on sponges of the family Dysideidae, and if you have a look at a few examples of dysideid sponges on the Forum [see messages #2826, #11334, #19789] you will see it does indeed have a remarkable resemblance to such a sponge. I am sure the pale network in the skin is not a network of muscle fibres but a colour pattern to match the spongin fibres found in the fibrous skeleton of dysideid sponges..

I guess it is surprising just how few chromodorids have used camouflage as part of their defensive strategy. The best example is Verconia verconis, which mimics the darwinellid sponges it feeds on, but I suspect this Ceratosoma will turn out to be just as good a mimic - once we find it on its food. I will call it Ceratosoma sp. 2.

Best wishes,
Bill Rudman

Rudman, W.B., 2007 (Apr 27). Comment on A new sponge-mimicking Ceratosoma by Ing. Harald Sapper. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/19565